Pseudogap phenomena near the BKT transition of a two-dimensional ultracold Fermi gas in the crossover region

Abstract

We investigate strong-coupling properties of a two-dimensional ultracold Fermi gas in the normal phase. In the three-dimensional case, it has been shown that the so-called pseudogap phenomena can be well described by a (non-self-consistent) $T$-matrix approximation (TMA). In the two-dimensional case, while this strong coupling theory can explain the pseudogap phenomenon in the strong-coupling regime, it unphysically gives large pseudogap size in the crossover region, as well as in the weak-coupling regime. We show that this difficulty can be overcome when one improve TMA to include higher order pairing fluctuations within the framework of a self-consistent $T$-matrix approximation (SCTMA). The essence of this improvement is also explained. Since the observation of the BKT transition has recently been reported in a two-dimensional ${}^6$Li Fermi gas, our results would be useful for the study of strong-coupling physics associated with this quasi-long-range order.

7pages, 4 figures, Proceedings of QFS2016

References in corpus (10)

• Many-Body Physics with Ultracold Gases
• Using photoemission spectroscopy to probe a strongly interacting Fermi gas
• Resonantly-paired fermionic superfluids
• Observation of pseudogap behavior in a strongly interacting Fermi gas
• Radiofrequency spectroscopy of a strongly interacting two-dimensional Fermi gas
• Observation of a two-dimensional Fermi gas of atoms
• Observation of the Berezinskii-Kosterlitz-Thouless Phase Transition in an Ultracold Fermi Gas
• Observation of pair condensation in the quasi-2D BEC-BCS crossover
• Pseudo-gap pairing in ultracold Fermi atoms
• Pairing effects in the normal phase of a two-dimensional Fermi gas

Cited by in corpus (2)

• Precision Many-Body Study of the Berezinskii-Kosterlitz-Thouless Transition and Temperature-Dependent Properties in the Two-Dimensional Fermi Gas
• Pseudogap regime of a two-dimensional uniform Fermi gas